Initiation of a mimo communication

ABSTRACT

The present invention provides a method and apparatus for initiating a multiple input multiple output (MIMO) communication. The method and apparatus includes processing that begins by transmitting a frame formatted in accordance with a default MIMO active transmitter-receiver antenna configuration to a target receiver. The processing continues by receiving at least one response frame from the target receiver. The processing continues by determining a number of receiver antennas of the target receiver from the at least one response frame.

CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS ContinuationPriority Claim, 35 U.S.C. §120

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. §120, as a continuation, to the following U.S. Utility patentapplication which is hereby incorporated herein by reference in itsentirety and made part of the present U.S. Utility patent applicationfor all purposes:

-   1. U.S. Utility patent application Ser. No. 11/132,516, entitled    “INITIATION OF A MIMO COMMUNICATION,” filed May 19, 2005, pending,    which claims priority pursuant to 35 U.S.C. §119(e) to the following    U.S. Provisional Patent Application which is hereby incorporated    herein by reference in its entirety and made part of the present    U.S. Utility patent application for all purposes:    -   a. U.S. Provisional Patent Application Ser. No. 60/648,207,        entitled “INITIATION OF A MIMO COMMUNICATION,”, filed Jan. 28,        2005, now expired.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to wireless communication systems andmore particularly to multiple input multiple output (MIMO)communications.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, et cetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver is coupled to theantenna and includes a low noise amplifier, one or more intermediatefrequency stages, a filtering stage, and a data recovery stage. The lownoise amplifier receives inbound RF signals via the antenna andamplifies then. The one or more intermediate frequency stages mix theamplified RF signals with one or more local oscillations to convert theamplified RF signal into baseband signals or intermediate frequency (IF)signals. The filtering stage filters the baseband signals or the IFsignals to attenuate unwanted out of band signals to produce filteredsignals. The data recovery stage recovers raw data from the filteredsignals in accordance with the particular wireless communicationstandard.

As is also known, the transmitter includes a data modulation stage, oneor more intermediate frequency stages, and a power amplifier. The datamodulation stage converts raw data into baseband signals in accordancewith a particular wireless communication standard. The one or moreintermediate frequency stages mix the baseband signals with one or morelocal oscillations to produce RF signals. The power amplifier amplifiesthe RF signals prior to transmission via an antenna.

In many systems, the transmitter will include one antenna fortransmitting the RF signals, which are received by a single antenna, ormultiple antennas, of a receiver. When the receiver includes two or moreantennas, the receiver will select one of them to receive the incomingRF signals. In this instance, the wireless communication between thetransmitter and receiver is a single-output-single-input (SISO)communication, even if the receiver includes multiple antennas that areused as diversity antennas (i.e., selecting one of them to receive theincoming RF signals). For SISO wireless communications, a transceiverincludes one transmitter and one receiver. Currently, most wirelesslocal area networks (WLAN) that are IEEE 802.11, 802.11a, 802.11b, or802.11g employ SISO wireless communications.

Other types of wireless communications includesingle-input-multiple-output (SIMO), multiple-input-single-output(MISO), and multiple-input-multiple-output (MIMO). In a SIMO wirelesscommunication, a single transmitter processes data into radio frequencysignals that are transmitted to a receiver. The receiver includes two ormore antennas and two or more receiver paths. Each of the antennasreceives the RF signals and provides them to a corresponding receiverpath (e.g., LNA, down conversion module, filters, and ADCs). Each of thereceiver paths processes the received RF signals to produce digitalsignals, which are combined and then processed to recapture thetransmitted data.

For a multiple-input-single-output (MISO) wireless communication, thetransmitter includes two or more transmission paths (e.g., digital toanalog converter, filters, up-conversion module, and a power amplifier)that each converts a corresponding portion of baseband signals into RFsignals, which are transmitted via corresponding antennas to a receiver.The receiver includes a single receiver path that receives the multipleRF signals from the transmitter. In this instance, the receiver usesbeam forming to combine the multiple RF signals into one signal forprocessing.

For a multiple-input-multiple-output (MIMO) wireless communication, thetransmitter and receiver each include multiple paths. In such acommunication, the transmitter parallel processes data using a spatialand time encoding function to produce two or more streams of data. Thetransmitter includes multiple transmission paths to convert each streamof data into multiple RF signals. The receiver receives the multiple RFsignals via multiple receiver paths that recapture the streams of datautilizing a spatial and time decoding function. The recaptured streamsof data are combined and subsequently processed to recover the originaldata.

An issue with MIMO wireless communications is determining the number oftransmit antennas and the number of receive antennas to be used in acommunication. For instance, at the commencement of a MIMO wirelesscommunication, the transmitting device knows the number of antennas itincludes, but does not know the number of antennas of the targetedreceiving devices. To provide efficient MIMO wireless communications,the transmitting device needs to economically determine the number oftransmit antennas and receive antennas that will be used for acommunication.

Therefore, a need exists for a method and apparatus for initiating amultiple input multiple output (MIMO) wireless communication thatincludes selecting transmit antennas for use in a MIMO communication.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a wireless communication systemin accordance with the present invention;

FIG. 2 is a schematic block diagram of a wireless communication devicein accordance with the present invention;

FIG. 3 is a schematic block diagram of a transmitting device initiatinga MIMO wireless communication with a target receiving device inaccordance with the present invention;

FIG. 4 is a logic diagram of a method for initiating a MIMO wirelesscommunication by a transmitting device in accordance with the presentinvention; and

FIG. 5 is a logic diagram of a method for selecting transmit antennasfor a MIMO communication by a transmitting device in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram illustrating a communication system10 that includes a plurality of base stations and/or access points 12,16, a plurality of wireless communication devices 18-32 and a networkhardware component 34. Note that the network hardware 34, which may be arouter, switch, bridge, modem, system controller, et cetera provides awide area network connection 42 for the communication system 10. Furthernote that the wireless communication devices 18-32 may be laptop hostcomputers 18 and 26, personal digital assistant hosts 20 and 30,personal computer hosts 24 and 32 and/or cellular telephone hosts 22 and28. The details of the wireless communication devices will be describedin greater detail with reference to FIG. 2.

Wireless communication devices 22, 23, and 24 are located within anindependent basic service set (IBSS) area and communicate directly(i.e., point to point). In this configuration, these devices 22, 23, and24 may only communicate with each other. To communicate with otherwireless communication devices within the system 10 or to communicateoutside of the system 10, the devices 22, 23, and/or 24 need toaffiliate with one of the base stations or access points 12 or 16.

The base stations or access points 12, 16 are located within basicservice set (BSS) areas 11 and 13, respectively, and are operablycoupled to the network hardware 34 via local area network connections36, 38. Such a connection provides the base station or access point 1216 with connectivity to other devices within the system 10 and providesconnectivity to other networks via the WAN connection 42. To communicatewith the wireless communication devices within its BSS 11 or 13, each ofthe base stations or access points 12-16 has an associated antenna orantenna array. For instance, base station or access point 12 wirelesslycommunicates with wireless communication devices 18 and 20 while basestation or access point 16 wirelessly communicates with wirelesscommunication devices 26-32. Typically, the wireless communicationdevices register with a particular base station or access point 12, 16to receive services from the communication system 10.

Typically, base stations are used for cellular telephone systems andlike-type systems, while access points are used for in-home orin-building wireless networks (e.g., IEEE 802.11 and versions thereof,Bluetooth, and/or any other type of radio frequency based networkprotocol). Regardless of the particular type of communication system,each wireless communication device includes a built-in radio and/or iscoupled to a radio.

FIG. 2 is a schematic block diagram illustrating a wirelesscommunication device that includes the host device 18-32 and anassociated radio 60. For cellular telephone hosts, the radio 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radio 60 may be built-in or anexternally coupled component.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradio 60. For data received from the radio 60 (e.g., inbound data), theradio interface 54 provides the data to the processing module 50 forfurther processing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, et cetera such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radio 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, et cetera via the input interface 58 or generate the dataitself. For data received via the input interface 58, the processingmodule 50 may perform a corresponding host function on the data and/orroute it to the radio 60 via the radio interface 54.

Radio 60 includes a host interface 62, a baseband processing module 100,memory 65, a plurality of radio frequency (RF) transmitters 106-110, atransmit/receive (T/R) module 114, a plurality of antennas 81-85, aplurality of RF receivers 118-120, and a local oscillation module 74.The baseband processing module 100, in combination with operationalinstructions stored in memory 65, executes digital receiver functionsand digital transmitter functions, respectively. The digital receiverfunctions include, but are not limited to, digital intermediatefrequency to baseband conversion, demodulation, constellation demapping,decoding, de-interleaving, fast Fourier transform, cyclic prefixremoval, space and time decoding, and/or descrambling. The digitaltransmitter functions include, but are not limited to, scrambling,encoding, interleaving, constellation mapping, modulation, inverse fastFourier transform, cyclic prefix addition, space and time encoding,digital baseband to IF conversion, multiple input multiple output (MIMO)communication initiation as further described with reference to FIGS. 3and 4, and/or transmit antenna selection as further described withreference to FIG. 5. The baseband processing modules 100 may beimplemented using one or more processing devices. Such a processingdevice may be a microprocessor, micro-controller, digital signalprocessor, microcomputer, central processing unit, field programmablegate array, programmable logic device, state machine, logic circuitry,analog circuitry, digital circuitry, and/or any device that manipulatessignals (analog and/or digital) based on operational instructions. Thememory 65 may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, and/or any device that stores digital information.Note that when the processing module 100 implements one or more of itsfunctions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory storing the corresponding operationalinstructions is embedded with the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.

In operation, the radio 60 receives outbound data 94 from the hostdevice via the host interface 62. The baseband processing module 64receives the outbound data 88 and, based on a mode selection signal 102,produces one or more outbound symbol streams 90. The mode selectionsignal 102 will indicate a particular mode of operation that iscompliant with one or more specific modes of the various IEEE 802.11standards. For example, the mode selection signal 102 may indicate afrequency band of 2.4 GHz, a channel bandwidth of 20 or 22 MHz and amaximum bit rate of 54 megabits-per-second. In this general category,the mode selection signal will further indicate a particular rateranging from 1 megabit-per-second to 54 megabits-per-second. Inaddition, the mode selection signal will indicate a particular type ofmodulation, which includes, but is not limited to, Barker CodeModulation, BPSK, QPSK, CCK, 16 QAM and/or 64 QAM. The mode selectsignal 102 may also include a code rate, a number of coded bits persubcarrier (NBPSC), coded bits per OFDM symbol (NCBPS), and/or data bitsper OFDM symbol (NDBPS). The mode selection signal 102 may also indicatea particular channelization for the corresponding mode that provides achannel number and corresponding center frequency. The mode selectsignal 102 may further indicate a power spectral density mask value anda number of antennas to be initially used for a MIMO communication.

The baseband processing module 100, based on the mode selection signal102 produces one or more outbound symbol streams 104 from the outbounddata 94. For example, if the mode selection signal 102 indicates that asingle transmit antenna is being utilized for the particular mode thathas been selected, the baseband processing module 100 will produce asingle outbound symbol stream 104. Alternatively, if the mode selectsignal 102 indicates 2, 3 or 4 antennas, the baseband processing module100 will produce 2, 3 or 4 outbound symbol streams 104 from the outbounddata 94.

Depending on the number of outbound streams 104 produced by the basebandmodule 10, a corresponding number of the RF transmitters 106-110 will beenabled to convert the outbound symbol streams 104 into outbound RFsignals 112. In general, each of the RF transmitters 106-110 includes adigital filter and upsampling module, a digital to analog conversionmodule, an analog filter module, a frequency up conversion module, apower amplifier, and a radio frequency bandpass filter. The RFtransmitters 106-110 provide the outbound RF signals 112 to thetransmit/receive module 114, which provides each outbound RF signal to acorresponding antenna 81-85.

When the radio 60 is in the receive mode, the transmit/receive module114 receives one or more inbound RF signals 116 via the antennas 81-85and provides them to one or more RF receivers 118-122. Each of the RFreceivers 118-122 includes an RF bandpass filter, a low noise amplifier,programmable gain amplifier, a frequency down conversion module, ananalog filtering module, an analog to digital conversion module, and adigital filter and down sampling module. In operation, the RF receiver118-122 converts the inbound RF signals 116 into a corresponding numberof inbound symbol streams 124. The number of inbound symbol streams 124will correspond to the particular mode in which the data was received.The baseband processing module 100 converts the inbound symbol streams124 into inbound data 92, which is provided to the host device 18-32 viathe host interface 62.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the baseband processing module 100 and memory 65may be implemented on a second integrated circuit, and the remainingcomponents of the radio 60, less the antennas 81-85, may be implementedon a third integrated circuit. As an alternate example, the radio 60 maybe implemented on a single integrated circuit. As yet another example,the processing module 50 of the host device and the baseband processingmodule 100 may be a common processing device implemented on a singleintegrated circuit. Further, the memory 52 and memory 65 may beimplemented on a single integrated circuit and/or on the same integratedcircuit as the common processing modules of processing module 50 and thebaseband processing module 100.

FIG. 3 is a schematic block diagram of a transmitting device 130 (e.g.,one of the plurality of wireless communication devices 18-32 of FIG. 1)transmitting a default formatted frame 134 to a target receiving device132 (e.g., another one of the plurality of wireless communicationdevices 18-32 of FIG. 1). The default formatted frame 134 may betransmitted directly to the targeted receiving device 132 and/or via anaccess point.

The default formatted frame 134 may be constructed in a variety of waysto initiate a MIMO communication with the targeted receiving device 132.For example, the default formatted frame 134 may be based on an assumednumber of antennas of the targeted receiving device (e.g., 1, 2, 3, or 4antennas) and then constructed based space time encoding, spacefrequency encoding, beamforming, or a fixed M by N configuration.

When the default formatted frame 134 is constructed in accordance withspace time encoding, the frame 134 includes a header section thatcomprises a short training sequence (STS), a long training sequence(LTS), a signal field, and a service field. The STS, LTS, and signalfield are at a lowest rate (or some other default rate) based on thenumber of assumed antennas of the targeted receiving device 132. Withinthe signal and/or service field, the transmitting device 130 includes anindication of the number of available transmit antennas.

In response to the default formatted frame 134, the targeted receivingdevice 132 generates and subsequently transmits a response frame 136.The response frame 136 may be an acknowledgement of receipt of thedefault formatted frame 134 that includes an indication of the number ofits antennas. The indication of the number of receiving device antennasmay include the number of antennas, the configuration of the antennas,the type of antennas, and/or any other information regarding theantennas that would facilitate determining a frame format (e.g., numberof transmit antennas, data rate, modulation, number of receivingantennas, frequency band, and/or any other information pertaining to aparticular mode of operation) for an efficient MIMO communication. Ingeneral, an efficient MIMO communication is one that minimizes the usean RF channel or channels but still reliably conveys data between thedevices 130 and 132. For example, the devices 130 and 132 will typicallyestablish the MIMO communication using the largest channel bandwidth(e.g., 20 MHz channel or 40 MHz channel), the highest data rate (e.g.,54 Mbps to approximately 500 Mbps), the highest modulation (e.g., 16 QAMor 64 QAM), etc. that the devices and allocated RF channel(s) cansupport.

Alternatively, the default formatted frame 134 may include a proberequest within the signal and/or service field to an access point, wherethe probe request is requesting the targeted receiving device toresponse with an indication of the number of its antennas. In responseto the probe request, the targeted receiving device 132, which may bethe access point or another wireless communication device, provides theresponse frame 136, which includes an indication of the receivingdevice's antenna configuration, via the access point to the transmittingdevice 130.

The transmitting device 130 interprets the response frame 136 todetermine the receiver's number of antennas and may also determine otherantenna configuration information regarding the receiver's antennas.From this information, the transmitting device 130 determines the numberof antennas it will use to provide an efficient MIMO communication. Inone embodiment, the transmitting device 130 will select a number oftransmitting antennas to match the number of receiving antennas. Inanother embodiment, the transmitting device 130 will select a greaternumber of transmitting antennas than receiving antennas for asymmetricalMIMO communication. The selection of which transmit antennas to use willbe described with reference to FIG. 5.

FIG. 4 is a logic diagram of a method for initiating a MIMO wirelesscommunication by a transmitting device. The process begins at step 140where the transmitting device transmits a frame formatted in accordancewith a default MIMO active transmitter-receiver antenna configuration toa target receiver. In one embodiment, the frame formatted in accordancewith the default MIMO active transmitter-receiver antenna configurationis a data frame that is based on an assumed number of receiver antennasand a corresponding number of transmit antennas. In another embodiment,the target receiver is an access point, where the frame is a proberequest.

The process then proceeds to step 142 where the transmitting devicereceives at least one response frame from the target receiver. In oneembodiment, the response frame is an acknowledgement that includes anindication of the receiver's number of antennas. In another embodiment,the response frame may be from an access point that includes a responseto a probe request frame. In yet another embodiment, the response framemay include a signal and/or service field that includes an indication ofthe receiver's number of antennas.

The process then proceeds to step 144 where the transmitting devicedetermines a number of receiver antennas of the target receiver from theat least one response frame. The process then proceeds to step 146 wherethe transmitting device reconfigures the MIMO activetransmitter-receiver antenna configuration from the default MIMO activetransmitter-receiver antenna configuration based on the at least oneresponse frame. In one embodiment, the transmitting device reconfiguresthe active transmitter-receiver antenna configuration such that thenumber of transmit antennas equals the number of receiver antennas. Inanother embodiment, the transmitting device reconfigures the activetransmitter-receiver antenna configuration such that the number oftransmit antennas is greater than the number of receiver antennas forasymmetric MIMO communications. Regardless of the particularreconfiguration, the transmitting device may further determine which ofa plurality of transmitter antennas to include in the reconfigured MIMOactive transmitter-receiver antenna configuration based on at least oneof supported date rate and a predetermined grouping of the plurality oftransmitter antennas.

FIG. 5 is a logic diagram of a method for selecting transmit antennasfor a MIMO communication by a transmitting device. The process begins atstep 150 where the transmitting device determines a number of receiverantennas of a targeted receiver, wherein the number of receiver antennasis less than a number of transmitter antennas. The process then proceedsto step 152 where the transmitting device equates a number of activetransmitter antennas to the number of receiver antennas.

The process then proceeds to step 154 where the transmitting deviceselects a set of the transmitter antennas based on the number of activetransmitter antennas to produce a selected set of transmitter antennas.In one embodiment, the transmitting device selects the set of thetransmitter antennas by selecting the set of the transmitter antennasfrom a list of predetermined groupings of the plurality of transmitterantennas, wherein a number of the transmitter antennas in a groupingcorresponds to the number of receive antennas.

The process then proceeds to step 156 where the transmitting devicetransmits a frame to the targeted receiver via the selected set oftransmitter antennas. In one embodiment, the frame has a given datarate, which may be set from the lowest data rate for the antennaconfiguration to the highest data rate for the antenna configuration.For example, the data rate may be set at the highest data rate or atsome mid point data rate.

The process then proceeds to step 158 where the transmitting devicedetermines whether an acknowledgement has been received for the framewithin a given time period or within a given number of retransmissionsof the frame. If not, the process proceeds to step 162 where thetransmitting device selects another set of the transmitter antennas whenan acknowledgement of receipt of the frame is not received from thetargeted receiver. If the acknowledgement is received, the processproceeds to step 160 where the transmitting device uses the selectedtransmitter antennas. As an alternative to step 160, the transmittingdevice may increase the data rate and varying the transmit antennaconfiguration to determine if a different transmit antenna configurationwill provide a higher data rate.

As one of ordinary skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term and/or relativitybetween items. Such an industry-accepted tolerance ranges from less thanone percent to twenty percent and corresponds to, but is not limited to,component values, integrated circuit process variations, temperaturevariations, rise and fall times, and/or thermal noise. Such relativitybetween items ranges from a difference of a few percent to magnitudedifferences. As one of ordinary skill in the art will furtherappreciate, the term “operably coupled”, as may be used herein, includesdirect coupling and indirect coupling via another component, element,circuit, or module where, for indirect coupling, the interveningcomponent, element, circuit, or module does not modify the informationof a signal but may adjust its current level, voltage level, and/orpower level. As one of ordinary skill in the art will also appreciate,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two elementsin the same manner as “operably coupled”. As one of ordinary skill inthe art will further appreciate, the term “compares favorably”, as maybe used herein, indicates that a comparison between two or moreelements, items, signals, etc., provides a desired relationship. Forexample, when the desired relationship is that signal 1 has a greatermagnitude than signal 2, a favorable comparison may be achieved when themagnitude of signal 1 is greater than that of signal 2 or when themagnitude of signal 2 is less than that of signal 1.

The preceding discussion has presented a method and apparatus forinitiating a MIMO communication and selecting transmitter antennasassociated therewith. As one of average skill in the art willappreciate, other embodiments may be derived from the teachings of thepresent invention without deviating from the scope of the claims.

What is claimed is:
 1. A method for establishing a multiple inputmultiple output (MIMO) communication by a transmitter, the methodcomprises: generating a first frame, wherein the first frame isformatted in accordance with a first particular mode of operation incompliance with an IEEE 802.11 standard mode of operation indicated by amode selection signal; transmitting the first frame to a target receiverover a first MIMO configuration of a plurality of transmitter antennas,wherein the first MIMO configuration is indicated by the mode selectionsignal; receiving at least one response frame from the target receiver;generating a second frame to the target receiver, wherein the secondframe is formatted in accordance with a second particular mode ofoperation in compliance with another IEEE 802.11 standard mode ofoperation indicated by the mode selection signal, wherein the secondparticular mode of operation indicated by a mode selection signal isbased on a highest supported data rate and largest channel bandwidthsupported by an allocated RF channel and the transmitter and the targetreceiver; and transmitting the second frame to the target receiver overa second MIMO configuration of the plurality of transmitter antennas,wherein the second MIMO configuration is indicated by the mode selectionsignal.
 2. The method of claim 1 wherein the mode selection signalfurther indicates a particular rate, a type of modulation, a code rate,a number of coded bits per subcarrier, and coded bits per OFDM symbolfor the second particular mode of operation.
 3. The method of claim 2wherein the mode selection signal further indicates a particularchannelization, a channel number and corresponding center frequency forthe second particular mode of operation.
 4. The method of claim 1wherein the second particular mode of operation indicated by the modeselection signal includes a largest channel bandwidth of either 40 MHzor 20 MHz.
 5. The method of claim 4 wherein the second particular modeof operation indicated by a mode selection signal includes a highestsupported data rate in a range of 54 Mbps to approximately 500 Mbps. 6.The method of claim 5 wherein the second particular mode of operationindicated by a mode selection signal is further based on a highestmodulation supported by an allocated RF channel and the transmitter andthe target receiver.
 7. The method of claim 1 wherein the second MIMOconfiguration of transmitter antennas indicated by the mode selectionsignal includes a number of antennas based on the highest supported datarate of the transmitter and the target receiver and a predeterminedgrouping of the plurality of transmitter antennas.
 8. The method ofclaim 7 wherein the first MIMO configuration indicated by the modeselection signal is a default MIMO active transmitter-receiver antennaconfiguration with a plurality of transmitter antennas.
 9. A transmitterfor establishing a multiple input multiple output (MIMO) communicationcomprising: a plurality of transmitter antennas; at least onetransmitter configuration module operably coupled to: transmit a firstframe to a target receiver over a first MIMO configuration of theplurality of transmitter antennas, wherein the first frame is formattedin accordance with a first particular mode of operation in compliancewith an IEEE 802.11 standard mode of operation indicated by a modeselection signal and wherein the first MIMO configuration is indicatedby the mode selection signal; and generate a second frame to the targetreceiver over a second MIMO configuration of the plurality oftransmitter antennas in response to receiving at least one responseframe from the target receiver, wherein the second frame is formatted inaccordance with a second particular mode of operation in compliance withan IEEE 802.11 standard mode of operation, wherein the second particularmode of operation is indicated by a mode selection signal based on ahighest supported data rate and largest channel bandwidth supported bythe transmitter and the target receiver and wherein the second MIMOconfiguration is indicated by the mode selection signal.
 10. Thetransmitter of claim 9 wherein the mode selection signal furtherindicates a particular rate, a type of modulation, a code rate, a numberof coded bits per subcarrier, and coded bits per OFDM symbol for thesecond particular mode of operation.
 11. The transmitter of claim 10wherein the mode selection signal further indicates a particularchannelization, a channel number and corresponding center frequency forthe second particular mode of operation.
 12. The transmitter of claim 11wherein the second particular mode of operation indicated by the modeselection signal includes a largest channel bandwidth of either 40 MHzor 20 MHz.
 13. The transmitter of claim 12 wherein the second particularmode of operation indicated by a mode selection signal includes ahighest supported data rate in a range of 54 Mbps to approximately 500Mbps.
 14. The transmitter of claim 13 wherein the second particular modeof operation indicated by a mode selection signal is further based on ahighest modulation supported by an allocated RF channel and thetransmitter and the target receiver.
 15. The transmitter of claim 9wherein the second MIMO configuration of transmitter antennas indicatedby the mode selection signal includes a number of antennas based on thehighest supported data rate of the transmitter and the target receiverand a predetermined grouping of the plurality of transmitter antennas.16. The transmitter of claim 15 wherein the first MIMO configurationindicated by the mode selection signal is a default MIMO activetransmitter-receiver antenna configuration with a plurality oftransmitter antennas.
 17. The transmitter of claim 9, wherein the atleast one response frame from the target receiver includes a number ofreceiver antennas of the target receiver.
 18. The transmitter of claim17, wherein the first frame is a data frame and the response frame is anacknowledgement frame.
 19. The transmitter of claim 17, wherein thefirst frame is a probe request, the target receiver is an access point,and the response frame is a response to the probe request.
 20. Thetransmitter of claim 9, further including: a plurality of transmittersections operably coupled to the plurality of transmitter antennas,wherein each of the plurality of transmitter sections converts abaseband signal into an RF signal.